A conventional telescopic rod includes a small-diameter rod segment, a large-diameter rod segment telescopically joinable to the small-diameter rod segment, and a locking unit surrounding the large-diameter rod segment. The locking unit is displaceable between an untightened state, where the small-diameter rod segment is slidable relative to the large-diameter rod segment, and a tightened state, where the large-diameter rod segment is forced by the locking unit into locking engagement with the small-diameter rod segment to thereby prevent movement of the small-diameter rod segment relative to the large-diameter rod segment.
The large-diameter rod segment 1 shown in FIG. 1 has a non-deformable region 10 and a deformable region 11. The deformable region 11 has a slot 111 extending from an open insertion end 113 of the large-diameter rod segment 1, through which the small-diameter rod segment (not shown) is inserted into the large-diameter rod segment 1, to terminate at a closed end 112 adjacent to the non-deformable region 10. When the locking unit is in the tightened state, the deformable region 11 is squeezed and deformed so that the diameter thereof is reduced.
The large-diameter rod segment 1′ shown in FIG. 2 is similar to that shown in FIG. 1, except that the slot 111′ in FIG. 2 is widened at the closed end 112′.
However, both the large-diameter rod segments 1, 1′ shown in FIGS. 1 and 2 suffer from the problem that, in the tightened state, deformation at the closed end 112 or 112′ is limited by the non-deformable region 10 or 10′, so that the reduction in diameter of the deformable region 11 or 11′ is not uniform in the tightened state. Thus, the deformable region 11 or 11′ of the large-diameter rod segment 1 or 1′ may not be in full locking engagement with the small-diameter rod segment. As a result, the small-diameter rod segment may undesirably move relative to the large-diameter rod segment 11 or 11′ in the tightened state.